Because of the extremely high temperatures existing in a gas turbine engine combustor the shell of the combustor must be protected. This is accomplished with liners supported on the wall of the combustor.
A float wall liner is shown in U.S. Pat. No. 4,302,941 issued to Thomas L. DuBell. The panels are supported in a floating manner which permits relative expansion without incurring high stress. Cooling air passes through openings in the shell and is impinged against the cold side of the liner panels. The flow then passes both upstream and downstream behind the panel with respect to the gas flow in the combustor. A smooth flow exits from the downstream side of each panel passing smoothly over the gas side surface of the downstream panel. The upstream passing flow cools the upstream portion of the panel, turns and mixes with the flow exiting from the upstream panel. This achieves effective cooling of the liner panels with the minimum flow.
Minimum turbulence is desired to minimize the mixing of the hot gas with the surface cooling flow, which would increase the temperature of the gas gripping the panel surface.
When the shell sections diverge with respect to one another the conventional cooling panel protrudes into the gas flow a considerable amount, thereby increasing the turbulence. The discharge flow from this panel is also substantially angled away from the downstream panel decreasing the effectiveness of the cooling. A bent panel bridging the angle change of the shell would accomplish the cooling, but would provide too much stiffness to accommodate the thermal differential expansion.